OMAHA, Neb. (AP) ConAgra Foods says moisture from a leaky roof and faulty sprinkler was the source of salmonella bacteria that contaminated peanut butter at its Georgia plant last year.

The bacteria made at least 425 people sick in 44 states -- including Oklahoma.

At least 12 cases of salmonella in Oklahoma were linked to the peanut butter. No deaths have been confirmed but Oklahoma officials were trying to determine if the death of a Tulsa man could be linked to the bacteria.

Health officials say the man was already suffering from an undisclosed illness before his death last month.

ConAgra spokeswoman Stephanie Childs said today the roof of the plant in Georgia leaked during a rainstorm and the sprinkler system went off twice because of a faulty sprinkler.

Childs says the moisture from the three events mixed with dormant salmonella bacteria in the plant that she says likely came from raw peanuts and peanut dust.